Conventionally, to have the comfort of wearing an in-line skate, a rubber foot pad is adhered to the insole of the in-line skate shoe body by adhesive. However, since roller skating comprises motions such as leaping, pivoting and serpentine, and the in-line skate shoe body is usually made of hard materials and covers a wearer's ankle to block the wearer from pivoting the ankle to reduce the shocks in roller skating, the conventional rubber foot pad cannot provide a sufficient shock absorbing function. Therefore, the legs and the feet of the wearer are usually uncomfortable and are even injured.
Further, after using for a period of time, due to the wearer's weight acting thereon, the rubber foot pad deforms permanently and can no longer achieve the desired cushioning and shock absorbing functions. In addition, after long time use, the adhesive hardens and loses its intended function such that the foot pad separates from the shoe body and is displaced, whereby the foot pad not only doesn't have the functions of cushioning and absorbing shocks, it even prevents the wearer from wearing the in-line skates.
In addition to the rubber foot pad, a conventional air cushion foot pad is used. As shown in FIGS. 1 and 2, the conventional air cushion foot pad is generally a hollow and closed foot pad, which utilizes the air pressure within the foot pad to provide the effect of resilient support. Moreover, the thickness of the pad is substantially the same and no support is provided within the pad. Therefore, while wearing the in-line skate, the air cushion foot pad is pressed and deformed under the wearer's weight and even the upper surface of the foot pad contacts with the lower surface thereof. Consequently, the desired cushioning and shock absorbing functions cannot be obtained.
Further, if the air cushion foot pad is pierced or worn out, air within the foot pad will leak out and the pad will no longer provide resilient support. The conventional air cushion foot pad also has the problem of easily separating from the in-line skate shoe body.
Moreover, to meet the ergonomic requirements, the sole of a conventional in-line skate shoe is generally made so that it inclines slightly forward; or, when viewed horizontally, the heel portion 90 of the sole is slightly higher than the toe portion 80 thereof (see FIG. 3). Conventionally, the heel portion 90 of the sole is made slightly thicker than the toe portion 80 thereof, or the sole of the in-line skate shoe is attached to the wheels in a predetermined angle, so as to obtain a forward inclined configuration which makes wearing the in-line skate comfortable and meets the ergonomic requirements. However, since the above inclined configuration is predetermined and cannot be easily changed due to the cost of designing, manufacturing and marketing, it does not meet some users' specific requirements (such as a larger inclined angle or no inclined angle).